What file did you delete?
It may still be in your recycle bin. Look at it and see if you can see the file extention.
From what you are stating, it looks like you deleted an operating system file and not the JPG with the picture.
Do you have a system restore point dated before you deleted the file you deleted?
Now, what you experienced was a browser hijacking.
After you restore your computer's ability to display wallpaper download, install update and run some of the anti-spyware - anti-malware aps listed below, particularly Spybot Search and Destroy and trhe Microsoft Anti-malware beta.Anti-malware freeware
(You can run as many of these as you wish. Generally there is no conflict between these and you should always run several)
Microsoft Antispyware Beta: http://www.microsoft.com/athome/security/s...re/default.mspx
Spybot S&D: http://www.safer-networking.org/en/index.html
Microsoft Malicious Software Removal Tool (Win XP and Win 2000):http://www.microsoft.com/security/malwareremove/default.mspx
A≤ - Free from http://www.majorgeeks.com/download4281.html
. Run it, click Search for Updates, then click Scan.
CWShredder from InterMute
CW Shredder removes some variants of spyware known as the Coolwebsearch Trojan. The Trojan takes advantage of a flaw in a key component of Windows -- Microsoft's version of the Java Virtual Machine -- to install itself via popups often found on porn and illegal software (a.k.a. "warez") sites. Run CWShredder after installing, and have it look for updates. Then click the "Fix" button, and the program will both scan and fix any problems it finds. If your system does not have this kind of spyware, it will give you the good news.
Install but do not attempt to repair anything by yoiurself with Hijack This.
What you should do is follow the instructions on the next link.How to get help using Hijack This and get a team memberís assistance:http://www.bleepingcomputer.com/forums/How...s_Log-t956.html