hi, when scanning with malwarebytes today it took 5 hours and 51 minutes, this is a new computer so this was strange. on my old computer with xp it took under 1 hour to scan.
the folder wich took extremely long to scan was windows\winsxs. the computer has windows vista. why does it take so long to scan? avast also scans for spyware but that took about 50 minutes.

Greetings and welcome .

The winsxs directory in Vista is imfamous for being HUGE and that's why Malwarebytes' takes so long to scan it. For future reference (and to save yourself a lot of time) the Quick Scan will catch 99.99% of all infections that the Full Scan will because of the way that Malwarebytes' is designed.

so using the full scan is necessary only if an infection is suspected? when for examle quick scan finds malware in the computers memory. how often should we scan with malwarebytes and other security software?

some security software that i have used requires you to right click and select "run as administrator" to be able to use some of its functions, is that required with malwarebytes too? or all security software?

I usually recommend running a Quick Scan about once a week (after updating definitions of course). There's no need to run it as admin, since, in Vista it automatically requests admin privelages (User Account Control should prompt you whenever you try to run Malwarebytes'). As far as doing the Full Scan, it's seldom necessary even when the system IS infected because of the way the Quick Scan is designed to work. It checks all known primary locations that malware likes to hide (like memory, the registry, temp folders, the desktop, Program Files, the Windows and system folders etc). That's why we always recommend the Quick Scan over the full scan. The only scenarios I've seen that would warrant a Full Scan involve things like infected flash drives or if you were scanning the system drive from another computer connected to your own (although the latter is not advised since Malwarebytes' is primarily designed to find active infections on a running system).

i used the quick scan now, it took only about two minutes i did however update the bios before scanning now so maybe that maked it even faster too.
thanks for your recommendations

You're very welcome . Yes, the quick scan is very fast, and also effective. Updating your bios could certainly have improved your overall system performance as well.

The speed of an anti-virus or anti-malware scan depends on a variety of factors.

• The program itself and how its scanning engine is designed to scan: using a signature database vs heuristic scanning for suspicious behavior or a combination of both.
• Options to scan for spyware, adware, riskware and potentially unwanted or unsafe programs (PUPs).
• Options to scan memory, boot sectors, registry and alternate data streams (ADS).
• Type of scan performed: Deep, Quick or Custom scanning.
• What action has to be performed when malware is detected.
• Type of operating system installed on the computer.
• A computer's hard drive size.
• Disk used capacity (number of files to include temporary files) that have to be scanned.
• Types of files (.exe, .dll, .tmp, .sys, .cab, archived, compressed, packed, email, etc) that are scanned.
• Whether external drives are included in the scan.
• Competition for and utilization of system resources by the scanner.
• Other running processes and programs in the background.
• Interference from malware.
• Interference from the user.