Every time I plug in my ext hard drive I get a blue screen with this problem IRQL NOT LESS OR EQUAL.
I've used the system recovery disc to install last setting that worked but has not corrected it.
This problem also occurs when I plug the external hard drive into my laptop.
Is the External Hard drive corrupted, is it recoverable?
It sounds like it may be corrupt. Usually when this happens on a PC or Laptop it means a few things, may need to update non-windows drivers, may need to update to latest service pack, may have an issue with RAM. On an External HD it usually means it is corrupted. you can try to wipe it and reformat it and see if it is useable, unfortunately your data will be gone. You can always take it to a data recovery specialist if the info is irreplaceable or data that is needed. they usually cost a lot though.