Personally, I chose not to install LinkScanner or the "security toolbar."
(Then again, I'm running Site Advisor free and am quite satisfied with it.)

I've seen several posts in the newsgroups and forums where LinkScanner's
caused browsing to slow to a crawl (and worse).  YMMV.

If you've already got AVG Free v8.0 installed, want to keep using it, and
are encountering problems or find that it's slowing down your machine, try
the following:

1. Download a fresh copy of the installer, saving it to your C: drive (i.e,
C:\avg_free_stf_en_8_100a1295.exe) =>
http://www.grisoft.cz/filedir/inst/avg_free_stf_en_8_100a1295.exe

2. Uninstall AVG 8.0 via Add/Remove Programs & reboot.

NB: You're "working without a net" now: Don't to ANYTHING else online (e.g.,
browsing; reading email; chatting) until you've got AVG 8.0 installed,
properly configured, and updated!

3. Carefully follow these instructions to (re)install AVG 8.0:
http://free.grisoft.com/ww.faq.num-1338

Tip: Do NOT install the toolbar (if offered) or either of the email
scanners.  Email Scanning provides no additional protection, it's a major
source of corruption and problems in Outlook Express/Windows Mail, and even
Symantec(NAV) says it's not necessary:
[quote]Disabling Email Scanning does not leave you unprotected against
viruses that are distributed as email attachments. Norton AntiVirus
Auto-Protect scans incoming files as they are saved to your hard drive,
including email and email attachments. Email Scanning is just another layer
on top of this. To make sure that Auto-Protect is providing the maximum
protection, keep Auto-Protect enabled and run LiveUpdate regularly to ensure
that you have the most recent virus definitions. [/quote] Source:
http://service1.symantec.com/SUPPORT/nav.nsf/docid/2002111812533106

4. Configure AVG as you wish via the User Interface | Tools | Advanced
settings

5. Check for and install any available updates.