Dell Studio 15 runs slow... My Dell studio 1558 takes long time to boot & processing is also slow,i have tried disk cleanup and defragment hard disk but nothing worked,it has the following configuration : Intel i5 processor,4GB RAM ATI Radeon HD 5740 Graphics card Windows 7 Home Premium Plz suggest a way to make it work faster...

Shelisha, may be you have too many programs to start with. That slows you down. Also extensions take time too. Try cleaning up and keep most used. Rest can go into a folder. Clean registry and clutter. I use advanced uninstaller pro. Have you defragmented the hard drive(s).

maybe is the hard disk... u must try to log in with a live usb linux (or windows or hirens boot cd ) and watch if it logs.. if u want to check fan if its covered of dust ill let u a link of how to open it http://www.youtube.com/watch?v=Hn_RX56oGqI

according to my research Western Digital My Passport 1TB is the best external hard drive

I would not consider replacing the motherboard, in fact Dell should be replacing the laptop for a design that does not have these heat related issues, I think if you made enough noise about this particular line they may replace what you have lost.

The optical unit uses 2 separate lasers to read the cd and dvd disks. In your case the laser for the dvd has failed.
This is unfixable, the entire optical unit will have to be replaced - it will cost you about $100 at a repair shop.

You can eject cd's by right clicking on Computer (from your Start Menu) then right click on the drive you'd like to eject. There should be an option to do so.

sound like your core is geting hot is your fan working is so try cleaning it with small birst of air plus check your bios settings..if not overheating try factory settings...

Here is the Dell service manual page where it shows the disassembling of the Dell 1558.
You will have to remove the DVD module to eject the DVD
Procedural steps are on this page site.

http://support.dell.com/support/edocs/systems/studio1558/en/index.htm

Check the BIOS for PC Health settings. It is possible that you have put a low value for "Critical Temperature", which makes the Laptop to turn off.

The computer needs maintenance periodically just like a car needs servicing. The computer generates temporary files when it is running and these consume hard disk space if they are not removed, also these files will slow down your computer.
To service your computer you should at lease once a month do a Disk Cleanup and a Defrag.
The Recycle bin should be emptied periodically.

To do a Disk Cleanup Click on My Computer, then right click on the C Drive, then click on Properties, then Disk Cleanup, then tick all the boxes to recover the hard disk space. (This process could take a few hours depending when it was last done and the size of the hard disk).

To do a Defrag, click on Programs, click on Accessories, then System Tools, then Defrag. then select the C Drive, then start the Defrag.

Again this will take a long time, you may want to start these processes overnight, don't stop them let them run till they finish. The next time you run them, it will not take as long.