I have a Dell Dimension 3100 and think the DVD drive is on its way out. Is there any diagnostic software to check this theory? If it has gone would I be able to use a SATA drive?

That computer has two SATA ports so you can have one hard drive and one DVD if you want.

This limits you if you ever want a second hard drive.

As to diagnostic:

What is the problem? Details please.

Every time I try to burn a cd/dvd it either spits the disc out saying its not empty or it freezes the program (both roxio and nero) and cannot access My Computer (not responding)

Can you play discs?

Did it use to work ok?

yes it can play discs and i have used a laser lens cleaner. It was fine until a couple of days ago. The last thing it worked on was when i erased a DVD RW

You could try this:

CD drive filters etc.
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If you feel comfortable editing the registry, here are some steps:

Click the Start button, click Run. In the Open box, type regedit and then click OK.
Click the plus sign (+) next to HKEY_LOCAL_MACHINE.
Click the plus sign (+) next to SYSTEM.
Click the plus sign (+) next to CurrentControlSet.
Click the plus sign (+) next to Control.
Click the plus sign (+) next to Class.
Click {4D36E965-E325-11CE-BFC1-08002BE10318}.

Once here click File in the upper left corner and choose: Export (this key)
Export to your Documents as a backup. If needed you can go back to this file and Import it back.

Then:

On the right hand side of the window, click UpperFilters.
Click Edit on the menu bar.
Click Delete, and then click OK.
On the right-hand side of the window, click LowerFilters.
Click Edit on the menu bar.
Click Delete, and then click OK.
Click File, and then click Exit. Restart the computer normally

Can't find upperfilters (not there) would it be easier to buy a new dvd. Also if i bought a SATA dvd would i be able to use it alongside an ide hard drive or would there be some conflict?

That computer has one IDE channel for two IDE drives.

It also has two SATA channels for two SATA drives.

There is no conflict using both IDE and SATA together.

I just question that if the drive can read but not write it might be a software issue.

You could try removing both Roxio and Nero and then just reinstall one of them.

Did you try to uninstall/reinstall drive?
Another option:
Go to Device Manager, click a "+" sign next to IDE ATA/ATAPI Controllers.
You'll see two items:
- ATA Channel0 (or Primary Channel)
- ATA Channel1 (or Secondary Channel)
Right click on each of them, and click Uninstal. Confirm.
Restart Windows. They'll be automatically reinstalled.