[PCWorld]

Post your comments for Can You Install a Program onto an External Hard Drive? here

[Vailhem]

I'd go one further than the article takes it. If your intention for doing this is because you're running out of space on your primary harddrive, then, it'd better to move the non-program essential files to an external harddrive (ex: mp3's, pictures, documents, etc) and only use the C: as a drive to install and run programs from. Not only should this make the computer faster, as its not accessing files for the programs from the same drive as its also trying to run the program from, it also makes it easier to salvage your data in event of a system crash... as the only thing that you'd lose would be the install of the operating system and the programs installed, which you should have the original on cd/dvd or be able to redownload again.
With today's harddrives being so large, and laptops easily coming with 80gb harddrives as a minimum standard now, you should never run out of storage space for programs. I have over 50 programs installed on my computer and am barely over 15GB's, including the operating system.
If you are running out of C: space, just buy an external drive, copy all your data to it, and that should free up space on your c: also allowing more space for the operating system to use as virtual ram.

If your intentions to do this are to move programs from one computer to another, w/out having to install the program on both computers, you could 'thin'-stall it. I suggest this program. http://portableapps.com/ that will allow you to install a program to a usb key and move it from computer to computer w/out having to install it on each computer.

[LitlJay]

Mind your licenses when doing this, though! Portable versions of Firefox and Thunderbird to allow private browsing on public/others' machines as well as keeping your personal settings/data in your pocket are great.
Trying to run your copy of Halo 3 on a friend's computer probably won't work and isn't legal, anyway.

[number6]

I do it all the time. I put all my most useful programs on a flash drive and carry it with me. CCleaner is one of them. A lot of the time you don't even need a portable version of the software to run it from an external memory device.

[taustin1382]

I will push it another step.

howas a fully functional OS on a thumb drive sound :D

http://www.slax.org/

[LitlJay]

Slax, BartPE, Knoppix, even the latest versions of Suse come with a utility for making your own custom boot image that can be installed on a pen drive, and they all work great. I have an 8 GB pen drive that has its own boot menu that allows a boot to all 9 XP cd images, a few vista images, gparted, ghost, partition magic, knoppix, easy recovery, spinrite, and a few other good tools. It saves me from having to lug a wallet full of CD's to client sites. This is a great idea, but I suspect the Q that led to the post was someone wanting to use software illegally this way.

[rgreen4]

Since he did not say that he wanted to do this to run it from another machine, which would be not only improper, but most likely not possible, we will give him the benefit of the doubt that he is doing it because of HD space. If you were to install something on the order of Microsoft Office on the external drive and them plug the drive into a second machine, it would not even get to the point of reading the COA as it would be missing all the parts that are scattered about in the Windows directories. Even an older version of Quicken will not run in this mode (I tried it years ago as an experiment).