[Eric in Tahoe]

I had thought I was protected by an elderly version of eTrust that came with my machine, until I got hit with the SpyGuard 2009 thing. I had MBAM already installed and it killed that phoney program, but then also did VundoH (twice). So I dumped eTrust and DL'd AVG8.5, which then found (and healed) at different times Huer infections (different groups of letters after the Huer name). Since that time, I have had issues with videocard drivers, and worse with trying to stay online.
I cannot stay connected for more than an hour each time (with cable internet) and it hasn't mattered whether I use the LAN or an ethernet adapter/USB combo. It seems to be an issue with the DHCP, but I have no idea how to repair. I tried upgrading my mobo driver, but that made it impossible to even boot. Unsure what's going on or whether this is the right place for my post but I am worried that my system may be damaged from these ongoing attack/issues. I can give whatever other details needed.

Win XP Home SP3
Nvidia firewall
AVG 8.5
MBAM
Spybot S&D
all updated

Last night's AVG 8.5 scan came up with:
"C:\Documents and Settings\EJ\Local Settings\Application Data\Mozilla\Firefox\Profiles\uucyd5p1.default\Cache\EAD31899d01";"Trojan horse Exploit_c.AHC";"Moved to Virus Vault"
"C:\Recycled\Dc3.tmp";"Trojan horse Exploit_c.AHC";"Moved to Virus Vault"
"C:\Recycled\Dc4.tmp";"Trojan horse Exploit_c.AHC";"Moved to Virus Vault"

I have no idea where these keep coming from, or whether my software is catching everything. System still acting strange, also just noticed that from time to time the screen will "blink" black for a half second then return to normal. This is most noticeable on start-up where it happens 2 or 3 times.

Eric