Helping people with computers... one answer at a time.
Software often accumulates on your machine, and much of it remains unused. You can leave it alone, but there are things to check for.
I have a number of large programs installed which I seldom use. Other than occupying disc space is it not a good idea to leave little used programs on the drive?
One reason why I am reluctant to remove them is that I have mislaid a few of the installation discs. If I copy the installed program to disc and try to reinstall it the wizard is unable to do so. Presumably some files have been lost during installation. Is there a way to overcome this problem?
If you're not worried about disk space there's nothing wrong with leaving software you don't use on your machine. There is at least one thing you should check, though.
As for ways to reinstall software for which you've lost the installation disks, that's a thorny issue without a clear answer.
The most common reason for kicking off unused software is disk space. But with disks being so very large and inexpensive, that's not the issue that it once was.
And to be really clear: if disk space is the only issue, and it's not an issue for you, then I'd leave things alone. I have lots of programs on my machine that I don't use, or don't use often, and simply haven't bothered to take the time to uninstall or remove. Once in a while in a fit of cleanliness I might uninstall something that's obviously never going to get used again, but often only on my laptop where I have a smaller hard disk.
However disk space may not be the only issue.
While I don't necessarily uninstall a lot of software, I do check the following:
Startup Items - a lot of software installs items that run automatically at start-up. Some go away after they run, serving only to slow down your system startup time. Others remain running, eating up some amount of your processor and available memory, and often adding an icon to the notification area of your task bar. I scan my startup items carefully and remove any that are not critical, or any that are clearly part of software that I don't use often. It's not always easy to know what's critical, but it's often very easy to identify a few things you know you don't need.
Desktop Icons - I know, I'm kinda different this way, but I have between 3 and 5 icons on my desktop, and that's all. I figure my desktop's covered most of the time anyway, so why have a lot of stuff on it? So I typically delete all but a few desktop icons, just to keep it clean.
Quick Launch Icons - I use the quick launch bar a lot. Unfortunately many applications insist that they're so important that they need to be there too. They don't. Particularly for software I'm not using, I just delete the shortcuts in the quick launch toolbar on my task bar.
You'll note one thing I did not mention: the start menu itself. For any program that remains on my machine, the I leave the start menu alone. If I decide I do want to run the application, I can find it there.
Now, about not having install disks for a lot of your software...
First, let me emphasize one thing: backup your system using one of the commercially available backup tools that backs up everything. It sounds like those applications reside only on your hard disk - if you had a failure, then most of those applications would be lost forever. A good backup program would allow you to restore to a known working snapshot of your system.
This is also one of the reasons I so strongly recommend getting installation CDs with your system, even if the software is all pre-installed. Failures happen, and if you have nothing to reinstall from, you're probably out of luck.
As a general rule, there's no blanket answer. Many programs will simply work if you copy them from one machine to another. Typically these are smaller applications and utilities that don't need a complex setup. Larger applications and application suites, however, typically require their setup. If you don't have the installation media, you may well be out of luck.
One thing to check for, regardless of application, is the vendor's web site. You may be able to download updates or new versions of applications you already own. What you'll want to do now is see if, depending on the application, you can record a registration code or activation key from within the software. Save those somewhere in case the downloaded update requires it.