If there is some sort of problem with the install (such as your computer system not having the bare minimum requirements...like 1gig of ram) you will not be able to "roll" back the update. The new dongle will be live. What does this mean... well, XP and Win7 can roll back the software, but the Aladdin hasp dongle, is not part of the rollback safety net.
So lesson to learn, before you go to v6, make darn sure that you have 30 gig of space on your hard drive, 1 gig worth of ram,Windows XP SP2, and a single core 1ghz processor.
So where do you find all this good info?
Go to your START>CONTROLPANEL>SYSTEM.
The window that opens will show you all of the relevant info on your machine.
So take care when you update, and look at what you have on your machine BEFORE you run the install! If not, you may be looking at buying a new pc or updating your ram, or hard drive, or other system upgrade!