I/O device error on external hard drive

Hi folks. I have a Dell GX240 running Windows XP Pro with Pentium 4 and 512 ram of memory. I have a Maxtor 200GB external hard drive hooked up to it. I keep all my photos and music there along with a system backup. Everthing was running just fine until I decided to run a disk cleanup on the drive. Since then certain folders are not accesible. I get an error message with a red X that reads:
G:\my Music\shared music\paul mccartney is not accesible
The request could not be performed because of an I/O device error.

What can I do to fix this? I cannot even delete mentioned folder either. Will I be able to restore these folders? Help

 

do a system restore back to before the problem.
there is no data loss

 

Thank you for responding. I'll give it a shot

 

I tried the sytem restore to an earlier date. I got a message that it could not perform the system restore.