So as of late one of my PCs got infected by a virus

.The reason being is because it is a family PC and everyone has access to it, one day one of the household members downloaded something and now its causing issues.
First I did the regular MBAM scan and the following came up:
Code:
Malwarebytes Anti-Malware 1.62.0.1300
www.malwarebytes.org
Database version: v2012.07.27.11
Windows 7 Service Pack 1 x86 NTFS
Internet Explorer 9.0.8112.16421
Ion :: ION-PC [administrator]
7/27/2012 7:14:54 PM
mbam-log-2012-07-27 (19-14-54).txt
Scan type: Full scan (C:\|)
Scan options enabled: Memory | Startup | Registry | File System | Heuristics/Extra | Heuristics/Shuriken | PUP | PUM
Scan options disabled: P2P
Objects scanned: 280611
Time elapsed: 1 hour(s), 5 minute(s), 38 second(s)
Memory Processes Detected: 0
(No malicious items detected)
Memory Modules Detected: 0
(No malicious items detected)
Registry Keys Detected: 5
HKCR\CLSID\{CA4520F3-AE13-4FB1-A513-58E23991C86D} (Trojan.Downloader) -> Quarantined and deleted successfully.
HKCR\gencrawler_gc.GenCrawler (Trojan.Downloader) -> Quarantined and deleted successfully.
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{CA4520F3-AE13-4FB1-A513-58E23991C86D} (Trojan.Downloader) -> Quarantined and deleted successfully.
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Ext\Settings\{CA4520F3-AE13-4FB1-A513-58E23991C86D} (Trojan.Downloader) -> Quarantined and deleted successfully.
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Ext\Stats\{CA4520F3-AE13-4FB1-A513-58E23991C86D} (Trojan.Downloader) -> Quarantined and deleted successfully.
Registry Values Detected: 0
(No malicious items detected)
Registry Data Items Detected: 0
(No malicious items detected)
Folders Detected: 0
(No malicious items detected)
Files Detected: 3
C:\Users\Ion\Uploads\Mixcraft\patch\acoustica.mixcraft.5.2.build.151-MPT.exe (PUP.Hacktool.Patcher) -> No action taken.
C:\Users\Ion\Uploads\Sony Acid Pro 7e\keygen\Keygen.exe (RiskWare.Tool.CK) -> No action taken.
C:\Users\Ion\AppData\Roaming\Media Finder\Extensions\gencrawler_gc.dll (Trojan.Downloader) -> Quarantined and deleted successfully.
(end) But after clearing those I still have issues:
1)unwanted addons to IE9and Chrome
2) automatic tabs to spam sites opening
3) system slows down way too much
I am running MBAM again to make sure it picks anything up but some help would be appreciated.