Hello,
Subject: ad keeps popping up (ad.doubleclick.net) and will not stop.

current virus software used: Webroot - does not detect any problems.

I have followed the suggestion on yahoo and added 127.0.0.1ad.doubleclick.net in the last line of my host file. That did not work.

I have downloaded hijackthis and ran it but I do not see anything in the log with the name listed above.

Does anyone have any suggestions on how I can safely get rid of this popup?  

Clay
"Without ambition, one starts nothing. Without work and determination, one finishes nothing. The prize will not be sent to you. You have to win it."[/b]

1. Download, Install, Quick Scan, and remove, with Malwarebytes AntiMalware.
2. Do the same with SuperAntiSpyware FREE Edition.
3. You may want to try a different Antivirus as well - Avira Antivir is the strongest, it seems.  Nod32 may be better if you want to pay... then again, the paid version of Avira is also very good.
4. If you don't have a firewalled router, get one - anywhere from $15 to $50 for a good/decent/basic one.  You can look online - Amazon, eBay, NewEgg.com, etc., or you can pick one up at an office supply store, Target, maybe WalMart - WalMart sells more tech items online than in store, last I checked.
5. Software firewall - if you don't have one, get one.  2 best are Online Armor and Comodo Internet Security, both have free and paid versions as well.  Online Armor (last I checked) doesn't have a 64 bit version, so bear that in mind.)
6. If you seem to be rid of the issue after the first couple scans, then download,  install, clean, with CCleaner, and/or Advanced System Care, Glary Utilities.  You can find all 3 at www.download.com  CCleaner gives you item by item inspection for the registry portion if you prefer, gives you a detail list of what it removes in the "cleanup" portion, as well as config options there... the other two are more one-click operations, I use all 3 all the time, not a problem with any of the 3.
7. If the problem seems to be gone, and you've got all the rest done, you also need to get rid of old restore points, in case an infection was copied there.  Best way to do is disable system restore, reboot, re-enable system restore, and set a new restore point.

Also, it wouldn't hurt to download one of the "safe" hostfiles available online.  One member, pechengs always recommends this, and he's got one or two listed in other threads.

In general, if you want to block all sorts of ads, (at least for FireFox and Google Chrome, I know), you can install the plugins: AdBlockPlus(FireFox) and AdBlock(Chrome).  I know they've both worked for me very well - I've not checked as to what's currently the best for IE, as I hardly use it.

If you want to make sure it's clean after all that, then run a new hijackthis log, and post here for a final confirmation.