Advice on cookie problem?

[chrimbow]

The first symtoms I noticed was when I tried to go on youtube, I got an error message -

Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.
Cookie: VISITOR(loads of letters/numbers)
Apache Server at www.youtube.com Port 80

When I clear cookies, all worked fine. Then I started to notice problems logging into web based mail etc. Again, When I clear cookies everything works OK. Obviously its a pain to keep clearing the cookies as it means I keep having to log into sites etc that I use.
I had a look at the list of cookies, most seem to be advertising type things but also some are for sites that I know I havent visited since I cleared cookies.
I have done a full scan with Avast which picked up nothing.
Any ideas, this is getting annoying

Thanks

[Flash477]

Now that is a very strange problem. Cookies should only ever be a couple of k and should never be large enough to cause that kind of problem.

If you have a look at your list of cookies what size are they?
What browser are you using?

[chrimbow]

Thanks for replying- LOADS of cookies mainly with "ad" in the name. I use FF3.

[vaughan]

run anti-spyware software, and try hijackthis aswell.. avast is anti-virus not anti-spyware

[chrimbow]

Tried everything so I gave it the annual format and all is OK now...

Thanks

[watercooled]

If you're using Firefox, this might prevent it from happening: Tools>options>privacy and under cookies, untick 'accept third party cookies'. Also install the add on called adblock plus.

[chrimbow]

If you're using Firefox, this might prevent it from happening: Tools>options>privacy and under cookies, untick 'accept third party cookies'. Also install the add on called adblock plus.

Thanks

[whoops]

Just for the record I have had similar problems with XP and Vista, got in a right old mess and downloaded a free program called "Malwarebytes", and was very doubtful of outcome, however it cleared the whole system of crap, adware, trojans, browser helpers, and sorted registry good style. Only other options I had were reformatting etc, did not need to. This worked after antispyware etc did not.

[ARBY]

I also used "Malwarebytes", and can confirm it did a good job with XP.