You don't say what your os is but assuming you have xp or later have you tried pressing F8 as it boots and, instead of repair, select 'Last known Good Configuration.'?
Can you remember what changes you made prior to this happening?
Huawei P10 review
1995-2015: How technology has changed the world in 20 years
An overview: What leading creative agencies are doing to improve diversity
New iPad, iPhone SE & Red iPhone 7 on sale now
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.