does the coding really have an effect on the website?
Absolutely. Invalid code can make search engines choke on the page -- search engines like google are now penalizing slow loading and poorly written pages. Bad code can mean massive accessibility failings, and bloated code increases the cost to host it. Poor programming practices that lead to code bloat or broken accessibility can make users bounce before the page even finishes loading; accessibility failings in particular. The lack of graceful degradation thanks to "what it looks like first" design and practices would certainly count me amongst those who would bounce before I ever even got to see your prices; and thanks to the 'tab' scripttardery and illegible font sizes I probably wouldn't have noticed you have 8 more plans hidden in there.
... and it ALWAYS costs more to maintain bloated poorly written code in the long term. There's way too much "get it looking pretty on the screen in front of me and to hell with the rest" going on right now, and the entire Internet is becoming less and less useful because of it.
This is even more true when you get to forms, which for example your shopping cart? UHG... no LABEL, no FIELDSET, tables for layout on non-tabular data, it's an accessibility mess so unless someone is at the magical combination of screen size and default font sizes you happen to be at, you'd be lucky to be able to complete a form!
Particularly with a lot of crap like INPUT and BUTTON outside of forms, and much of it having zero graceful degradation scripting off. That's bad code, and YES, that can have a major impact your conversions, AND your search rankings.
To be brutally frank (when am I ever anything but?) the cart page on the hosting subdomain is such a mess, it's a miracle it works for anyone anywhere! It reeks of being built by someone who never bothered learning HTML in the first place, and instead being slapped together in some rubbish WYSIWYG or something.
I think main area isn't really the coding but maybe the way how I am placing certain things.
That's certainly part of it too -- like that giant cloud thing circling the planet? I'd swing an axe at that immediately. Nobody's gonna sit there waiting to read the stuff you're sliding in and out either, and of course design elements like that are incompatible with elastic design, which in my book means they have no business on websites in the first place.
I'd probably swing an axe at that, put all the text that's in it at the bottom or in an about page, get rid of the tabbed nonsense at the bottom, and make the main content your twelve VPS plans; aka THE THING YOU ARE TRYING TO SELL! Think about that, what's actually important on the page, some tiny sliding in and out text that means nothing to anyone, or your products and pricings? You're trying to sell hosting, top and center should be your rates and plans.
Likewise a lot of your sub-pages have color legibility issues too -- yellow on green for example falls way short of accessibility minimums and is likely invisible to a good chunk of the population.
It might be tricky, but I'd consider moving all the 'about us' type stuff to subpages, and getting ALL your services and plans into a 'squeeze' page as the home page, since every single one of them would be a 'call to action'. People land on your site that's the FIRST thing they should be seeing.
NOT some flashy but ultimately useless animated nonsense and photoshop jockey images chewing up the whole screen and making the site painfully slow to load, painfully slow to use, and, well... just painfully slow. Given what you have for CONTENT, I would HIGHLY advise getting your total image sizes down to 48k in 6 images or less; if some visual element that is NOT content cannot fit into those constraints, it doesn't belong on the page.
Also, you might simply try using image optimization and proper formats; JPEG is more efficient even if it's lossy, palettized PNG is great for most mono-hue images in the 17 to 256 color range, and GIF is great if you can get down to 16 colors or less... The 24 bit alpha transparency png files? Well, take this mess:
At half a megabyte that is by itself eight times what I'd allow an entire page template (not counting content or social plugins) HTML+CSS+Scripts+images to ever reach on a site. No, not joking. Generally I consider the ideal size for a page template (again, not counting content and social scripts) to be 72k in 12 files or less; and unless it's something like an image gallery I generally have an upper limit of 144k in 24 files once my content is plugged in. (though again not counting social plugins, they're big, but they are usually also cached).
I mean, I'm looking at your site, and thinking that most of your pages have no excuse to be more than 32k in 8 files or less, other than the "JS for nothing" and artsy template graphics nobody ACTUALLY cares about.
Since again, people visit websites for the content, not the goofy graphics or goofier scripted nonsense you hang on it.
Said image also shoe-horns you into a fixed width layout with fixed height content in that area, which is most always /FAIL/ at web development. It's companion:
... at a quarter megabyte is also disastrously bad, particularly when there's no reason for it to be so big. That latter one if it was precomposited over the white, then made palette transparency for "close enough anti-aliasing" could be dropped to under 90k in size, but even at that size that's larger than I'd ever allow a template image on a site to be, as by itself even optimized it would still be 25% larger than I usually allocate for an entire template!