Yes it does. Though it doesn't really matter how many you have, but how big they are. One 1,000MB program will slow down a computer more than two 1KB programs.

Nope, UNLESS you almost filled up your hard drive, in which case, yes, cus windows would be hunting for space to write its temp. files etc and it would slow things up.

Yes they can if you are giving windows too much work to do it seems to rebel. .

Typically if you fill your hard drive past 80% capacity you begin to lose productivity because it's jockeying for temporary memory space. Also it's how many programs you have running either actively or in the background that has an impact as well. If the programs are on there, but are just stored as data until they are run, you should be alright. I used to always run out of disk space and had to keep upgrading my hard drive.

Having more programs installed doesn't slow down your computer, but having too many unnecessary programs running does. Programs that are running are using up your memory (RAM) leaving less free RAM for other programs. Lots of programs that you install automatically set themselves to run as soon as Windows starts, despite the fact that you may not want to use them. The first step is to look at the system tray at the bottom right hand corner to see SOME of the autorun programs. If you don't use some of them every time you use your computer you need to stop them from aut-running at startup. Do this by clicking the start button and then clicing on Run. Type msconfig and then click OK. In the dialog box that comes up click the radio button next to Selective start up and click on the tab labelled Startup. You can now de-select anything you don't want to run automatically at startup. You can always launch any of these programs later if you want to use them. As somebody else has mentioned, don't let your HDD get too full because the Windows swap file needs quite a bit of space. Also if you see your hard drive light flashing a lot while your working it would be a good idea to add more RAM. Last point - run defrag regularly.

And hvaing a lot of programs all running at the same time slows it down than just quantity. Those programs that start at startup in your system tray, the virus or time, or weather, or whatever is in there, will really slow things for you. For some games you have to turn them off, even your screensaver so you can play.

Besides the hard drive space issue, and the running many programs at the same time issue brought up already, it will slow Windows down a bit because of all the extra registry entries. But this isn't constant slowness, it tends to be more pronounced at bootup. Also, each new program may install a helper program in the system tray and that can also slow things down a little.

The main problem is if they are running (even in the background) and if your free diskspace is low. This will make your WIndows computer slow: - all anti-virus, popup blocking, spyware check, firewall. But usually, you need them. - many programs running at the same time - all security updates and patches for Windows and for your programs - program updates (not necessary, but nice) - some hardware ist just not enough to run some programs. With a normal onboard graphic card, it is difficult to run Vista. - if you use all the memory, Windows swaps on the disk. The swap space is usually managed automatically but it could run low. - it is better to uninstall the program that you do not need. - many programs install a part which is always running in the background: If these are not security monitoring programs, this part would be better stopped (with options, msconfig or utilities) - scan your disks and defrag them regularly; defrag improve the speed - I hope not, but some virus or malware can make your computer slow... Here some complementary information: http://www.yoingco.com/slow_computer.htm http://users.telenet.be/bluepatchy/miekiemoes/slowcomputer.html http://www.thepcspy.com/articles/other/what_slows_windows_down/1