Uhhh... let me think
1 Run your virus-scanner, but beware, many modern viruses can circumvent (or hide from) anti-virus programs. Quarantine anything suspicious.
2 Make sure you are using a reputable antivirus. Some good free ones are Avira AntiVir, AVG, and Avast! NOD32 from Eset has the highest detection rate and lowest resource consumption, though it is not free.
3 In the event no viruses were found and your issue virus issue is still present follow these next steps.
4 Install Malware-bytes and update it, Don't scan for malware yet. Malware-bytes can be downloaded from here:
http://www.malwarebytes.org/mbam.php
5Other suggested scanners to run are “Spybot Search and Destroy” and “Superantispyware”.
6Depending on the Virus you might not be able to install any software or do updates, if this is the case skip to step 7 otherwise continue to step 6.
7 Reboot into “Safe Mode” - Restart your computer and press F8 before Windows loads. Press F8 several times if you need to. Select “Safe Mode” from the resulting menu. Safe Mode disables much of the start-up routine (Continue to step 9).
8 Reboot into "Safe Mode with Networking" - Restart your computer and press F8 before Windows loads. Press F8 several times if you need to. Select “Safe Mode with Networking” from the resulting menu. Safe Mode with Networking disables much of the start-up routine but allows the use of basic web browsing, allowing you to access to download and update Malware-bytes, Make sure you select full scan option instead of quick scan.
9O nce in safe mode with networking download malware-bytes from their website, install it and update it.
10 Run your Malware Scanners - Run both the scanners sequentially, deleting any references found. CAUTION!! When deleting infected files make sure you are not removing important files you require, E.g. Microsoft Outlook uses “.pst files” for your email, and often some emails within this “.pst file” are infected. Virus scanners will delete your complete “.pst file” so your entire email Inbox NOT just a single email!!
If you cannot boot to safe mode that's a bit above my head...