windows 7: Visual inconsistencies after infection

Hi - I have searched for anything I could find on this issue but so far no luck.
About a year ago I purchased a Dell XPS 430 with Windows Vista Home Premium 64 bit, which I recently upgraded to Windows 7 via a retail copy of the W7 upgrade disk (also Home Premium). CPU is Intel Core2 Quad. Graphics card is ATI Radeon 3650 HD. I connect to the Web via Intel-made ethernet card connected directly to a 5 or 6 year old Motorola DOCSIS cable modem. After getting infected with several nasty trojans, I bought a Linksys RVS4000 Security Router but have not yet begun using it. I just finished formatting my hard drive using an XPSP2 retail copy, then reinstalling the Dell OEM Vista followed by the W7 upgrade DVD. It was a real pain to do, but I was having zero success in eradicating those trojans.

At the time of infection my AV was Kaspersky IS 2009, which I subsequently replaced with Avast. It became obvious immediately after the infection that something was wrong. My PC literally locked up and would barely work at all.
Kaspersky did detect heuristically a malicious file encrypter and removed it but could not delete the two encrypted archives it had created. After replacing KIS09 with Avast, I ran a scan and here's what it found:
W32/MalwareHider Patched-based! Maximus
HEUR/Malware (mmviewer.exe)
TR/Hijacker.Gen (fastscanner_v2.1.rar)
APPL/NirCmd.D.Z
APPL/PsExec.E
W32/SecRisk-Process Patcher-based! Maximus

So as I said, I have just now reinstalled everything from scratch. I have not yet connected to the Web.

Here's my question: As I am configuring Windows I am seeing a lot of visual inconsistencies among the various menus. One might have large, thin letters and a thin window border, while another might have very small, dark and blurry font with a thick border. I've never seen this before and it's got me spooked.

Please don't tell me that all my work reinstalling has failed to solve the problem. And if so, what on earth should I do now?

Thanks.
(Message posted via smartphone.)