shingamba, is it dual boot, and you can boot to Solus but not Windows?
If that's the right assumption, have you tried checking the windows partition with Gparted?
AFAIR, you can create an installation USB using an ISO downloaded from Microsoft that will allow you, on boot, options: either to install Windows or repair an existing Windows installation, that might be worth trying?
If it turns out the problem is a failing drive then you may be able to recover some data using testdisk
Both testdisk
and gparted
are available in Solus.
Description : TestDisk is powerful free data recovery software! It was primarily designed to help recover lost partitions and/or make non-booting disks bootable again when these symptoms are caused by faulty software, certain types of viruses or human error (such as accidentally deleting a Partition Table). Partition table recovery using TestDisk is really easy.
HTH