Go into your User.alx file.
It can be found in C:Documents and SettingsAll UsersDocumentsSTALKER-SHOC

Replace all the text with the following:

_preset Default
ai_use_torch_dynamic_lights on
unbindall
bind jump kSPACE
bind crouch kRCONTROL
bind crouch_toggle kSLASH
bind accel kLSHIFT
bind sprint_toggle kX
bind forward kUP
bind back kDOWN
bind lstrafe kLEFT
bind rstrafe kRIGHT
bind llookout kQ
bind rlookout kE
bind cam_zoom_in kADD
bind cam_zoom_out kSUBTRACT
bind torch kL
bind night_vision kN
bind wpn_1 k1
bind wpn_2 k2
bind wpn_3 k3
bind wpn_4 k4
bind wpn_5 k5
bind wpn_6 k6
bind artefact k7
bind wpn_next kY
bind wpn_fire mouse1
bind wpn_zoom mouse2
bind wpn_reload kR
bind wpn_func kV
bind wpn_firemode_prev k9
bind wpn_firemode_next k0
bind pause kPAUSE
bind drop kG
bind use kF
bind scores kTAB
bind chat kCOMMA
bind chat_team kPERIOD
bind screenshot kF12
bind quit kESCAPE
bind console kGRAVE
bind inventory kI
bind buy_menu kB
bind skin_menu kO
bind team_menu kU
bind active_jobs kP
bind map kM
bind contacts kH
bind vote_begin kF5
bind vote kF6
bind vote_yes kF7
bind vote_no kF8
bind speech_menu_0 kC
bind speech_menu_1 kZ
bind use_bandage kRBRACKET
bind use_medkit kLBRACKET
cam_inert 0.
cam_slide_inert 0.25
cl_cod_pickup_mode 1
cl_dynamiccrosshair on
g_always_run on
g_autopickup on
g_backrun on
g_corpsenum 10
g_eventdelay 0
g_game_difficulty gd_stalker
hud_crosshair on
hud_crosshair_dist off
mm_mm_net_srv_dedicated off
mm_net_con_publicserver off
mm_net_con_spectator 20
mm_net_con_spectator_on off
mm_net_srv_gamemode st_deathmatch
mm_net_srv_maxplayers 32
mm_net_srv_name BLACKBOX
mm_net_srv_reinforcement_type 1
mm_net_weather_rateofchange 1.
mouse_invert off
mouse_sens 0.32
net_cl_icurvesize 0
net_cl_icurvetype 0
net_cl_interpolation 0.
net_cl_log_data off
net_cl_pending_lim 3
net_cl_update_rate 30
net_dedicated_sleep 5
net_sv_log_data off
net_sv_pending_lim 3
net_sv_update_rate 30
ph_frequency 75.00000
ph_iterations 24
r1_dlights on
r1_dlights_clip 10.
r1_glows_per_frame 16
r1_lmodel_lerp 0.1
r1_pps_u -1.
r1_pps_v 0.
r1_ssa_lod_a 64.
r1_ssa_lod_b 48.
r1_tf_mipbias 0.
r2_aa off
r2_aa_break 0.800000,0.500000,0.000000
r2_aa_kernel 0.5
r2_aa_weight 0.250000,0.250000,0.000000
r2_allow_r1_lights off
r2_gi off
r2_gi_clip 0.001
r2_gi_depth 1
r2_gi_photons 16
r2_gi_refl 0.9
r2_gloss_factor 1.4
r2_ls_bloom_fast off
r2_ls_bloom_kernel_b 0.7