Over 900 computers of HP Elitedesk 800 G2 35W has crashed their harddrives the last week. In total the hospital has 1800 out of 5000 in this specific model. The harddrives has been a problem for quite some time (and other hospitals have experienced the same problem) but the last week the problems has increased making the hospital to go to "readiness state" (swedish stabsläge). The computers are 2-3 years old and was scheduled to be replaced in 2020-2021

That computer model is from Q42015. Warranty 3 years. It's about 4 years old.

And also, why do they don't have proper data backup solution to prevent of this?

Haven't they heard of Backups? Centrialized data storage server that doesn't harm the data because it's in a RAID so you just replace the drive and it will restore it self? Because if you're a SysOps/SysAdmin etc. you know once one drive start to fail, more will fail very soon... Which is also for security sake, the sensitive data shouldn't be placed on the client computers they use.