Hello! First time posting, I seem to have come across a situation that has me fairly concerned.
This morning I was browsing deviantart, a website I frequent several times a day with no problem. I then got Avast giving me a trojan virus warning,from the url I figure it was from one of the advertisement banners on the site, for which I hit the Abort Connection button, and it appeared as if one of the ad banners didn't load, assumed that was the culprit. I then proceeded to poke around the menus for instructions on how to report the ad to the site, and had the same warning pop up again, and gave the same address in the warning. Again, I used the Abort Connection.
I then ran a scan just to be sure, and the results showed zero infected files, but told me I had 2 'Decompression Bombs', which I've never seen before. There were no options to do anything with those files.
So, it may be a coincidence that I had 2 virus warnings and then 2 decompression bombs, but I'm sort of a paranoid person by nature

(and not the brightest when it comes to computer files) So I was wondering if there is any risk of trojans hiding in those bombs? And if there are any steps I should take?
I'm running the scan again, just in case, so I'll post the file names if they come up again
Thanks for taking the time to read

any help is much appreciated

(oh, I use Windows Vista if that makes any difference)