Get a utility such as "DiskCheckup" which can report the SMART counters to see exactly what counters are showing problems. The action you take probably depends on whether the issues are with connectivity or media issues, and how many errors there are.
I've downloaded Hard Drive Sentinel software which now indicated:
"Failure Predicted - Attribute: 5 Reallocated Sectors Count, Count of sectors moved to the spare area. Indicate problem with the disk surface or the read/write heads.
There are 869 bad sectors on the disk surface. The contents of these sectors were moved to the spare area.
The drive found 618 bad sectors during its self test.
Based on the number of remapping operations, the health of the disk was decreased in different steps.
There are 7364 weak sectors found on the disk surface. They may be remapped any time in the later use of the disk.
Replace hard disk immediately."
If I run disk cleanup now - will it solve the problem or crash my hard disk...?
Is there a way to change & recover or should I stop using the laptop until I replace the disk???
Are there any pending sectors? Those are the very worst because they're sectors that contain data which can't be read. If the drive was able to read the data it would move it to a reallocated sector, but if not, the sector stays pending. If you're unable to read those pending sectors, the data in them will be lost.
Disk cleanup won't do anything to recover the data on the bad sectors. It's real purpose is to delete unwanted files, not to fix bad media.
The number of bad sectors you have seems pretty high, I'd agree that it's probably a good idea to make sure you have a current backup and then think about getting another disk. If the reallocated sector count continues to climb then you're in dangerous territory indeed.