AntiVirus
Disabling Anti-virus rarely shuts it off it normally still runs in memory, you could try it but I doubt you'll see a change, the only way to be sure is to uninstall. There is no guarantee this is the problem, it is just something worth trying. What AV seems to work fine on one machine doesn't work well on others.
I personally have Norton but I don't recommend it and I won't be renewing it because they do not offer a 64-bit version which means if I run a 64-bit browser then I have limited protection.
For paid software
F-secure has been mentioned a few times on this forum and, locally, it is also the software that my ISP gives out free to it's subscribers. In that thread you can also see rankings for other good ones like GDATA and BITDEFENDER but I have never tried those.
MSE is not as good but it's free and we recommend it rather than going "naked".
I can never remember between AVG, AVAST, and AVIRA which one is good and which ones are often attributed with BSODs; I believe AVAST is recommended and AVG & AVIRA should be removed but I'm sure someone will come along and verify that as I've never used any of them.
W7 DVD
If the software came preinstalled then it is usually stored on a back-up partition and can be restored from there. But besides that, normally on the first boot, Windows recommends you create a system repair disk and if you have that then I was suggesting you try popping in that rather than a complete restore. Also if you determine that you do not have W7 on a backup partition (because your HD crashed or whatever) then it is possible to
download and burn a copy of W7 and then enter your key (I recommend doing this and writing your key on it just so you have a DVD). Most pre-built computers have OEM licenses because the manufacturer gets them cheaper that way but in return they are required to provide the support rather than Microsoft. The biggest issue with an OEM license is that you cannot transfer it to a new machine and even replacing your motherboard with a different mobo constitutes a new machine and invalidates your license. Another thing of note is that besides the standard install, most manufacturers add their own extras (much of which they get paid to "push" onto your machine) and none of that will be there on the W7 ISO copy; most of it you don't need but sometimes they include an on-screen volume indicator or software to use your touchpad or even programs like PowerDVD and NERO which you will need to get from the manufacturer or find an alternative.
Recommendation
So I would run a
system repair, even if you have to create it on another machine that has same version and bit-rate. If that doesn't resolve the issue, I would uninstall AVG completely, reboot, and see if it works. Reinstall AVG if that wasn't the problem or install some other AV software so you are not "naked". Otherwise you can live with it or consider a complete reinstall paying close attention to the issues of missing manufacturer programs and the extra work required to back-up all your data/userids and having to reinstall all your software etc.