Not enough info and can you explain what switching towers entails?
Generally, this kind of a message means that the hard drive has problems
or has failed; however, you need to provide some specific information
including verbatim error messages in order to receive specific
recommendations.

Sarah
Enter  BIOS and  check that  the HDD is being detected  correctly, do this:
Boot and  hit  del to  enter  setup, next  tab to  autodetect HDD page, if
the HDD isn't  detected  at  this  point, shut down, disconnect  the  power
cable  from the  case, remove  the  cover  and  make  sure that the  power
and  ribbon cables  are  seated snugly.
No joy ? replace the  HDD.
If the  above  is  beyond  your  expertise, and  you  have  a  boot diskette
see  if  the  contents  of  the  C: drive  are  readable  after  starting
with the  diskette, type  the  following  command  from the A:\>  prompt:
C: <enter>
C:\>  dir /w <enter>
If you  get  the  same  error  message, most  likely  your  HDD has  failed.
One  other possibility for  the  message  is  that  the  CMOS battery needs
replacing, is  the  computer  more  that  5 years  old ?.

rgds
Li'l Roberto