Actually there are three best possible alternatives to bring the default icons back . These are ....
1. Laborious process ....
Icons - Change Using Resource Hacker .... and you need the appropriate icons to use .
2. Comparatively easier ... change the imageres.dll files in System32 and syswow64 with the files of the same build . If yours is SP1, I or anybody else can supply it to you .
3. Easiest way ....
Repair Install .... you just need the installer disk .
If any type of further assistance (like the system icons for first option, system files for the second option) is required , dont hesitate to ask . But
Repair Install will solve the issue rightly .