What does the above term mean?
What should one do in such a situation?
and my task bar has shifted from the bottom of the page to the left side !!
Windows uses "virtual memory" when it believes it has insufficient RAM memory (this is what we mean normally when we quote memory eg the typical 1 Gb of a modern system). Virtual memory is in fact space on your hard drive - its disadvantage is that it works much more slowly. Normally, Windows will allocate & manage memory although you can manually change settings if you wish.
If your PC has been working OK, I would be suspicious if it starts playing up. This could be due to many things - 1 possibility is a virus or some kind of malware.
Do you have a firewall and anti-virus program? Do you have kids that download stuff from the web eg? Do you make regular backups?
Nine's suggestion of a complete re-image (restore software from good copy kept on eg Acronis) will get you going again (in future perhaps!) but it's still important to diagnose the cause. You should backup all your data files soonest but if you have suffered any kind of corruption it may be sub optimal.
After that you could try a restore - this is easier than reloading Windows if you haven't got an "image" as described by Nine.
I think Nine's policy of reloading every 2 months or so is not strictly necessary, though it will certainly ensure a clean, good system - his description of Windows gradually slowing up is realistic but you can take measures to minimise this. I am very strict with not accepting cookies, ensuring firewall and several types of anti-malware programs are in use; I do not have any problems and my current copy of XP has been running satisfactorily for several years. I do run a small home network (currently 3 PCs) this way and have no problems (famous last words!).
It would be useful to know more symptoms of your problem: when it occurred, was it ok before, what protective software do you run, any backups, have you installed any new software or downloaded any.
Most important is to make some copies of your essential data - all the rest can be reloaded eventually (a pain, of course) assuming you have original disks etc.
Over to you. (long live the paperless office
)