Your site is far better than most of those which we're occasionally asked to comment on.
The site loads quickly (avoiding the use of the dreaded Flash animations which so many people seem to think are essential).
The site is clearly laid out, with a good choice of colour combinations.
There are a few grammatical errors but they're not particularly 'glaring'.
While most people are familiar with entering displayed characters (as an 'anti-spam' measure) when submitting contact forms, some might not be. (So a note saying "Please enter these characters into the box" might be useful).
The most obvious error, though, sees to be that your firm's name is hidden away at the foot of the page. Anyone visiting the website of GL Computers would normally expect to see that business name clearly displayed at the top of each page.
Chris