This file has been reported to be part of a spyware/malware/trojan. It is likely that the problem you are experiencing is linked directly to the spyware/malware/trojan rather than an actual missing DLL-file and the recommended course of action is to first locate/remove the Malware. We do not recommend downloading this file.
DLL-Files.com Support says:
This is a possible manual solution for you 'handyman-fixers' out there: (at your own risk)
Bs2.dll is related to the BookedSpace adware, used to display pop-up advertisement.
1. Click start, choose 'run'
2. Type 'cmd' - You should now have a DOS-commando window open.
3. Type cd "%WinDir%\System"
4. regsvr32 /u "..\rem00001.dll"
5. regsvr32 /u "..\bs2.dll"
6. regsvr32 /u "..\bs3.dll"
7. Click start, choose 'run'
8. Type 'regedit'
9. Find the key
and delete the entry 'BookedSpace' (BS2 variant) or 'Bsx3' (BS3 variant).
10. Reboot your computer
11. Delete the 'rem00001.dll', 'bs2.dll' or 'bs3.dll' file in the Windows folder.
12. Click start, choose 'run'
13. Type 'regedit'
14. delete the key
HKEY_LOCAL_MACHINE\Software\Remanent or HKEY_LOCAL_MACHINE_Software\BookedSpace